After the Security and Exchange Commission (SEC) announced its ban on stock-short selling, the WSJ says that "dozens of stocks and exchange-traded funds changed hands on electronic exchanges at bizarre prices. Some were more than double their closing levels Thursday; some were at unnaturally low prices, such as one penny."

Exchange officials blamed the problems on confusion over the SEC ban, as well as high trading volumes, but they can't pinpoint as of yet the root cause of the problem.

At least 40 stocks and as many as 80 many have been involved. Traders who thought they had won big and others who have been stuck with losses are not happy.